If its happening with the harpoon then there's not really much I can do. The weapon building system to use GMod props as weapon models will bug out occasionally. On SGM (and even AHG but not as often for some reason) after throwing a harpoon and it switching back to your primary/secondary weapon, your fingers would be pretty messed up. Without a thorough review of the weapon base code, this won't be fixed. I can leave this open but it probably won't be addressed until we attack other bugs that we can bang out quickly.